The Chinese capital saw its best air quality in recent years in the first six months of this year, with good air quality registered for more than 100 days, according to the Beijing Environmental Protection Bureau.

The monitoring figures show that the number of days with air quality marked as Class-2 or above - favorable indices in China's air standards - reached 109 days, or 27 days more than the same period last year, indicating an almost 15 percent rise.

The bureau said Class-3 air quality or above - average ratings in national air standards - was recorded for 179 days, accounting for 98.9 percent of the total six-month period.

There were just two days when air quality was Class-4 or below, meaning a condition of moderately heavy pollution, down by 11 days from the same period last year.

Experts attributed the air quality improvement to expanded use of low-sulfur coal in the city in the first three months of this year, and to the adding of desulfurizer to burning coal, reducing pollutant discharge.

Beijing has drafted a new five-year plan to clean up the environment and reduce air pollution by 2008, when it will host the Olympic Games.

Air pollution resulting from the use of coal as energy source, auto emissions and dust from construction sites are the leading environmental problems in Beijing, Beijing's Vice Mayor Liu Zhihua said.

The average density of inhalable particles, a key indicator of urban air pollution, remains 165 micrograms per cubic meter in Beijing, 65 micrograms too higher than the national standard.

Photochemical smog, which has struck some big cities in the United States, Japan and Australia, has occasionally occurred in Beijing during recent summers, Liu said at a national meeting on pollution control.

The city government has drafted a plan for the 2003-2007 period, aiming to improve the overall environment and ensure an ideal environment for the 2008 Olympics, he said.

One step toward that goal is reducing dependence on coal. By 2007, Beijing plans to supply 5 billion cubic meters of natural gas annually, pipelined from China's western region, compared with 1.8 billion last year, Liu said. Other measures to reduce coal consumption include increasing electricity production and use of clean energy.

Stricter standards on auto emissions will also be introduced in 2005. The city's emission standards are now in line with those in European Union countries in 1996.

It also plans to move more than 200 polluting factories out of the fourth ring road encircling the city.